This is decentralized voting web application. People can vote the favorite cryptocurrencies.

nodejs, npm, ganache-cli, metamask chrome plugin are installed

$ ganache-cli

copy one of the private key and in metamask click "Import Account" and paste the private key

$ npm install

$ truffle compile

$ truffle migrate

$ npm run dev

Then use http://127.0.0.1:8080/

Enter one of "Bitcoin", "Ethereum", "EOS" can click vote. The data will write to the blockchain. Refresh the page to see the result. In the metamask, make sure "localhost 8545" is selected as the network. Make sure the gas is at least 5 wei.

run the following command in the project directory

$ truffle test tests/TestVoting.sol

Pitfalls in Race Condition Solutions¶ Since race conditions can occur across multiple functions, and even multiple contracts, any solution aimed at preventing reentry will not be sufficient.